Radiation detector, radiographic imaging device, and radiographic imaging system

ABSTRACT

The present invention provides radiation detector, radiographic imaging device and radiographic imaging system that may detect irradiated radiation while maintaining quality of radiographic image. The radiation detector has: pixels having a sensor portion that generates charges in accordance with light converted from irradiated radiation, TFT switch that outputs, to a signal line, charges read-out from the sensor portion, and radiation detection TFT switch that is not connected to a signal line; and radiation detection pixels that have the sensor portion, the TFT switch, and radiation detection TFT switch that is connected to a signal line and that outputs, to the signal line, charges read-out from the sensor portion. The radiation detection TFT switches are connected to radiation detection scan lines, and ON/OFF states are controlled by scan signals that are outputted from a radiation detection control circuit.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority under 35 USC 119 from Japanese PatentApplication No. 2011-263016, filed on Nov. 30, 2011, the disclosure ofwhich is incorporated by reference herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a radiation detector, a radiographicimaging device, and a radiographic imaging system. In particular, thepresent invention relates to a radiation detector, a radiographicimaging device, and a radiographic imaging system for imagingradiographic images.

2. Description of the Related Art

There are conventionally known radiation detectors that are used inradiographic imaging devices for imaging radiographic images for thepurpose of medical diagnosis, or the like. The radiation detectordetects radiation, that has been irradiated from a radiation irradiatingdevice and has passed through a subject, and captures a radiographicimage. The radiation detector carries out imaging of a radiographicimage by collecting and reading-out charges that are generated inaccordance with the irradiated radiation.

A radiation detector that is formed from plural pixels that each have asensor portion, that is formed by a photoelectric conversion element orthe like and that generates charges due to the irradiation of radiationor of light converted from radiation, and a switching element, thatreads-out the charges generated at the sensor portion, is known as sucha radiation detector.

There is known a technique of providing, at this radiation detector,radiation detection pixels that have a short-circuited switchingelement, in order to carry out detection according to the irradiation ofradiation, such as the start of irradiation of radiation or the like(see, for example, Japanese Patent Application Laid-Open (JP-A) No.2011-174908).

In such a technique, at the radiation detection pixels, the switchingelements are short-circuited. Therefore, charges are read-out regardlessof the states of control (the on/off states) of these switchingelements. For example, an electric signal (charge amount), thatcorresponds to the charge read-out by the short-circuited switchingelement from a radiation detection pixel, and a predetermined thresholdvalue, are compared, and if the threshold value is exceeded, it isdetermined that the irradiation of radiation has started.

As in the technique disclosed in JP-A No. 2011-174908, when carrying outdetection according to the irradiation of radiation on the basis ofelectric signals read-out from radiation detection pixels, thedifference in the wiring capacities is extremely large at signal lines(hereinafter called “detection lines”) through which electric signalsread-out from radiation detection pixels flow (i.e., signal lines towhich radiation detection pixels are connected), and at signal lines(hereinafter called “regular lines”) through which electric signalsread-out from regular pixels flow (i.e., signal lines to which radiationdetection pixels are not connected, and through which electric signalsread-out from radiation detection pixels do not flow). When carrying outimaging of a radiographic image, there are cases in which the outputsignals of detection lines, to which radiation detection pixels areconnected, deteriorate, and a large difference arises between theseoutput signals and the output signals of regular lines.

When a large difference arises between the output signals of detectionlines and the output signals of regular lines, the image quality of thecaptured radiographic image may deteriorate.

In regard thereto, in order to maintain the level of image quality ofthe radiographic image, the detection lines are treated as defectivelines, and image correction is carried out on the basis of informationof the surrounding normal pixels (regular pixels). However, in the imagecorrection of line defects, in a unique pattern, correction artifactsare generated, and may become difficult to maintain the level of imagequality of the radiographic image.

SUMMARY OF THE INVENTION

The present invention provides a radiation detector, a radiographicimaging device, and a radiographic imaging system that may carry outdetection according to the irradiation of radiation while maintainingthe quality of a radiographic image.

A first aspect of the present invention is a radiation detectorincluding: plural first pixels including, a first sensor portion thatgenerates charges in accordance with irradiated radiation, and a firstswitching element that reads-out the charges generated at the firstsensor portion and outputs the charges to a signal line; plural secondpixels including, a second sensor portion that generates charges inaccordance with irradiated radiation, a second switching element thatreads-out the charges generated at the second sensor portion and outputsthe charges to a signal line, and a radiation detection switchingelement that reads-out the charges generated at the second sensorportion and outputs the charges to a signal line; plural scan lines thatare formed from at least one of a scan line group formed from scan linesto which control terminals of the first switching elements are connectedand through which control signals that switch the first switchingelements flow, and scan lines to which control terminals of the secondswitching elements are connected and through which control signals thatswitch the second switching elements flow, or a scan line group to whichthe control terminals of the first switching elements and the controlterminals of the second switching elements are connected and throughwhich control signals that switch the first switching elements and thesecond switching elements flow; and plural radiation detection scanlines that are provided between predetermined scan lines among theplurality of scan lines, and to which control terminals of the radiationdetection switching elements are connected, and through which radiationdetection control signals that switch the radiation detection switchingelements flow.

In a second aspect of the present invention, in the above first aspect,each of the first pixels may include the radiation detection switchingelement whose a control terminal is connected to the radiation detectionscan line and that is not connected to a signal line.

In a third aspect of the present invention, in the above aspects, thefirst pixels and the second pixels may be configured to have shapes thatare line-symmetrical across the radiation detection scan lines.

In a fourth aspect of the present invention, in the above aspects, theplural radiation detection scan lines may be connected, per eachpredetermined number thereof, to a radiation detection control circuitfrom which the radiation detection control signals are outputted.

A fifth aspect of the present invention is a radiographic imaging deviceincluding: the radiation detector of the above aspects; a radiationdetection control circuit that outputs the radiation detection controlsignals to the radiation detection switching elements of the radiationdetector; and detecting section for carrying out predetermined detectionaccording to irradiation of radiation, on the basis of electric signalscorresponding to charges that are outputted to the signal lines from theradiation detection witching elements of the second pixels.

In a sixth aspect of the present invention, in the above fifth aspect,during a detection period in which a start of irradiation of radiationis detected by the detecting section, control signals that set the firstswitching elements and the second switching elements in OFF states mayflow to the scan lines, and the radiation detection control signals thatset the radiation detection switching elements in ON states may flow tothe radiation detection scan lines.

In a seventh aspect of the present invention, in the above fifth andsixth aspects, during the detection period, a resetting operation, thatresets charges accumulated in the first pixels and the second pixels maybe repeated at a predetermined cycle, by flowing control signals thatset the first switching elements and the second switching elements in ONstates to the scan lines.

In an eighth aspect of the present invention, in the above fifth throughseventh aspects, when the first switching elements and the secondswitching elements are set in ON states and the charges for radiographicimage imaging are outputted from the first pixels and the second pixelsto the signal lines, the radiation detection switching elements may beset in OFF states.

A ninth aspect of the present invention is a radiographic imaging systemincluding: an irradiation device that irradiates radiation; and theradiographic imaging device of any one of the fifth through eightaspects that detects radiation irradiated from the irradiation deviceand acquires a radiographic image corresponding to detected radiation.

In accordance with the above aspects, present invention may provide aradiation detector, a radiographic imaging device, and a radiographicimaging system that may carry out detection according to the irradiationof radiation while maintaining the quality of a radiographic image.

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary embodiments of the present invention will be described indetail based on the following figures, wherein:

FIG. 1 is a schematic drawing showing the schematic configuration of aradiographic imaging system according to a present exemplary embodiment;

FIG. 2 is a schematic drawing showing the schematic configuration of aradiation detector according to the present exemplary embodiment;

FIG. 3 is a plan view showing the configuration of the radiationdetector according to the present exemplary embodiment;

FIG. 4 is a cross-sectional view along line A-A of a pixel 20A of theradiation detector according to the present exemplary embodiment and isshown in FIG. 3;

FIG. 5 is a cross-sectional view along line B-B of the pixel 20A of theradiation detector according to the present exemplary embodiment and isshown in FIG. 3;

FIG. 6 is a cross-sectional view along line C-C of a radiation detectionpixel 20B of the radiation detector according to the present exemplaryembodiment and is shown in FIG. 3;

FIG. 7 is a schematic drawing showing the schematic configuration of asignal detecting circuit of the radiation detector according to thepresent exemplary embodiment;

FIG. 8 is a schematic drawing that schematically shows the flow ofoperations at the time of imaging a radiographic image, of aradiographic imaging device according to the present exemplaryembodiment;

FIG. 9 is a time chart showing in detail the flow of operations at thetime of imaging a radiographic image, of the radiographic imaging deviceaccording to the present exemplary embodiment;

FIG. 10 is a time chart showing in detail another example of the flow ofoperations at the time of imaging a radiographic image, of theradiographic imaging device according to the present exemplaryembodiment;

FIG. 11 is an explanatory drawing for explaining a case of carrying outdetection according to the irradiation of radiation per block, in theradiographic imaging device according to the present exemplaryembodiment;

FIG. 12 is an explanatory drawing for explaining a case of carrying outdetection according to the irradiation of radiation per block, in theradiographic imaging device according to the present exemplaryembodiment;

FIG. 13 is a time chart showing in detail the flow of operations at thetime of detection (AEC) according to the irradiation of radiation, ofthe radiographic imaging device according to the present exemplaryembodiment; and

FIG. 14 is a drawing showing another example of the overallconfiguration of the radiation detector according to the presentexemplary embodiment.

DETAILED DESCRIPTION OF THE INVENTION

An example of a present exemplary embodiment is described hereinafterwith reference to the drawings.

First, the schematic configuration of a radiographic imaging system thatuses a radiation detector according to the present exemplary embodimentis described. FIG. 1 is a schematic drawing of an example of aradiographic imaging system of the present exemplary embodiment.

A radiographic imaging system 200 is configured to include a radiationirradiating device 204 that irradiates radiation (e.g., X-rays or thelike) onto a subject 206, a radiation imaging device 100 having aradiation detector 10 that detects radiation that has been irradiatedfrom the radiation irradiating device 204 and has passed through thesubject 206, and a control device 202 that instructs imaging ofradiographic images and acquires radiographic images from the radiationimaging device 100. Radiation, that has been irradiated from theradiation irradiating device 204 and that carries image information byhaving passed through the subject 206 who is positioned at an imagingposition, is irradiated onto the radiation imaging device 100 at atiming based on control of the control device 202.

The schematic configuration of the radiation imaging device 100 of thepresent exemplary embodiment is described next. In the present exemplaryembodiment, explanation is given of a case in which the presentinvention is applied to the indirect-conversion-type radiation detector10 that converts radiation, such as X-rays or the like, into light onceand converts the converted light into charges. In the present exemplaryembodiment, the radiation imaging device 100 is configured to includethe indirect-conversion-type radiation detector 10. Note that ascintillator that converts radiation into light is omitted from FIG. 2.

Plural pixels 20 are disposed in the form of a matrix at the radiationdetector 10. The pixel 20 is configured to include a sensor portion 103that receives light and generates charges and accumulates the generatedcharges, a TFT switch 4 that is a switching element for reading-out thecharges accumulated in the sensor portion 103, and a radiation detectionTFT switch 34 that is used in sensing according to the irradiation ofradiation. In the present exemplary embodiment, the sensor portion 103generates charges due to light, that has been converted by thescintillator, being irradiated thereon.

The plural pixels 20 are arranged in the form of a matrix in a onedirection (hereinafter also called the “scan line direction”) and in adirection (hereinafter also called the “signal line direction”) thatintersects the one direction. The array of the pixels 20 is illustratedin an abbreviated manner in FIG. 2, and, for example, 1024×1024 of thepixels 20 are arranged in the scan line direction and the signal linedirection.

In the present exemplary embodiment, radiation detection pixels 20B thatare used in detecting the irradiation of radiation, and other pixels 20A(mainly, pixels that are used only for detecting radiation andgenerating an image expressed by the radiation) are determined inadvance among the plural pixels 20. Note that, hereinafter, whenreferring generically to the pixels 20A and the radiation detectionpixels 20B without differentiating therebetween, they are simply calledthe pixels 20.

Plural scan lines 101, that are for turning the TFT switches 40N andOFF, and plural radiation detection scan lines 109, that are for turningthe radiation detection TFT switches 34 ON and OFF, are provided inparallel on a substrate 1 (see FIG. 4 through FIG. 6). Further, on theone hand, the scan lines 101 and the radiation detection scan lines 109,and, on the other hand, plural signal lines 3 for reading-out thecharges accumulated in the sensor portions 103, are provided so as tointersect one another. In the present exemplary embodiment, one of thesignal lines 3 is provided for each row of pixels in one direction, andone of the scan lines 101 is provided for each row of pixels in theintersecting direction. For example, in a case in which 1024×1024 of thepixels 20 are arranged in the scan line direction and the signal linedirection, there are 1024 of each of the signal lines 3 and the scanlines 101.

Further, as shown in FIG. 2, the radiation detection scan line 109 areprovided between the scan line 101 and the scan line 101, and the pixels20 of adjacent rows are configured so as to have line symmetry acrossthe radiation detection scan line 109. Therefore, in the presentexemplary embodiment, for example, in a case in which 1024×1024 of thepixels 20 are arranged in the row direction and the column direction asdescribed above, there are 1024/2=512 of the radiation detection scanlines 109.

A radiation detection control circuit 108, that outputs scan signals forturning the radiation detection TFT switches 340N and OFF to therespective radiation detection scan lines 109, is connected to therespective radiation detection scan lines 109.

Note that, in the present exemplary embodiment, each predeterminednumber of the radiation detection scan lines 109 are connectedcollectively (connected as a single radiation detection scan line 109)to the radiation detection control circuit 108. In the case shown inFIG. 2, the radiation detection scan line 109 that is provided betweenscan line 101(G8) and scan line 101(G7), and the radiation detectionscan line 109 that is provided between scan line 101(G6) and scan line101(G5), are connected to the radiation detection control circuit 108 asradiation detection scan line 109(Ch1). Similarly, the radiationdetection scan line 109 that is provided between scan line 101(G4) andscan line 101(G3), and the radiation detection scan line 109 that isprovided between scan line 101(G2) and scan line 101(G1), are connectedto the radiation detection control circuit 108 as radiation detectionscan line 109(Ch2). Further, although the radiation detection pixels 20Bare disposed only at one side with respect to the radiation detectionscan lines 109 in FIG. 2, the radiation detection pixels 20B may bedisposed at both sides with respect to the radiation detection scanlines 109. In this case, the detection sensitivity doubles.

Further, in the radiation detector 10, common electrode lines 25 areprovided parallel to the respective scan lines 3. The sensor portions103 are connected to the common electrode lines 25, and bias voltage isapplied to the sensor portions 103 from a bias power source (notillustrated) via the common electrode lines 25.

Scan signals for switching the respective TFT switches 4 flow to thescan lines 101. The respective TFT switches 4 are switched due to scansignals flowing to the respective scan lines 101. Further, scan signalsfor switching the respective radiation detection TFT switches 34 flow tothe radiation detection scan lines 109. The respective radiationdetection TFT switches 34 are switched due to scan signals flowing tothe respective radiation detection scan lines 109.

Electric signals, that correspond to the charges accumulated in therespective pixels 20, flow to the signal lines 3 in accordance with theswitched states of the TFT switches 4 and the radiation detection TFTswitches 34 of the respective pixels 20. More concretely, electricsignals corresponding to the accumulated charge amounts flow to thesignal line 3 due to any of the TFT switches 4 and radiation detectionTFT switches 34, that are connected to that signal line 3, being turnedON.

A signal detecting circuit 105, that detects the electric signals thathave flowed-out to the respective signal lines 3, is connected to therespective signal lines 3. Further, a scan signal control circuit 104,that outputs scan signals for turning the TFT switches 40N and OFF tothe respective scan lines 101, is connected to the respective scan lines101. In FIG. 2, in an abbreviated manner, one of each of the signaldetecting circuit 105 and the scan signal control circuit 104 are shown.However, for example, a plurality of the signal detecting circuits 105and a plurality of the scan signal control circuits 104 are provided,and a predetermined number (e.g., 256) of the signal lines 3 or the scanlines 101 are connected to each. For example, in a case in which 1024 ofeach of the signal lines 3 and the scan lines 101 are provided, four ofthe scan signal control circuits 104 are provided and 256 of the scanlines 101 are connected to each, and four of the signal detectingcircuits 105 also are provided and 256 of the signal lines 3 areconnected to each.

For each of the signal lines 3, the signal detecting circuit 105incorporates therein an amplification circuit (see FIG. 7) thatamplifies the inputted electric signal. At the signal detecting circuit105, the electric signals inputted from the respective signal lines areamplified by the amplification circuits, and are converted into digitalsignals by an ADC (analog/digital converter).

A control section 106 is connected to the signal detecting circuits 105,the scan signal control circuits 104, and the radiation detection scanlines 109. The control section 106 carries out predetermined process,such as noise removal and the like, on the digital signals converted atthe signal detecting circuits 105, and outputs, to the signal detectingcircuits 105, control signals expressing the timing of signal detection,and outputs, to the scan signal control circuits 104, control signalsexpressing the timing of output of the scan signals.

The control section 106 of the present exemplary embodiment isconfigured by a microcomputer, and includes a CPU (central processingunit), a ROM, a RAM, and a nonvolatile storage formed by a flash memoryor the like. The control section 106 carries out control for imagingradiographic images by executing, at the CPU, a program stored in theROM.

A plan view showing the configuration of the indirect-conversion-typeradiation detector 10 according to the present exemplary embodiment isshown in FIG. 3. A cross-sectional view along line A-A of the pixel 20Aof FIG. 3 is shown in FIG. 4. A cross-sectional view along line B-B ofthe pixel 20A of FIG. 3 is shown in FIG. 5. A cross-sectional view alongline C-C of the radiation detection pixel 20B of FIG. 3 is shown in FIG.6.

As shown in FIG. 4 and FIG. 5, at the pixels 20A of the radiationdetector 10, the scan lines 101 (see FIG. 3) and gate electrodes 2 areformed on the insulating substrate 1 that is formed from alkali-freeglass or the like, and the scan lines 101 and the gate electrodes 2 areconnected (see FIG. 3). The wiring layer at which the scan lines 101 andthe gate electrodes 2 are formed (hereinafter, this wiring layer is alsocalled a “first wiring layer”) is formed by using Al or Cu, or a layeredfilm formed mainly of Al or Cu. However, the material for forming thefirst wiring layer is not limited to these.

An insulating film 15 is formed on the entire surface on this firstsignal wiring layer. The region of the insulating film 15 that ispositioned above the gate electrode 2 works as a gate insulating film atthe TFT switch 4. The insulating film 15 is formed of, for example,SiN_(x) or the like, and by, for example, CVD (Chemical VaporDeposition).

Semiconductor active layers 8 are formed in shapes of islands above thegate electrodes 2 on the insulating film 15. The semiconductor activelayer 8 is the channel portion of the TFT switch 4, and is formed from,for example, an amorphous silicon film.

A source electrode 9 and a drain electrode 13 are formed at the upperlayer of these. Together with the source electrodes 9 and the drainelectrodes 13, the signal lines 3 are formed at the wiring layer atwhich the source electrodes 9 and the drain electrodes 13 are formed.The source electrodes 9 are connected to the signal lines 3 (see FIG.3). The wiring layer in which the source electrodes 9, the drainelectrodes 13 and the signal lines 3 are formed (hereinafter, thiswiring layer is also called a “second wiring layer”) is formed by usingAl or Cu, or a layered film formed mainly of Al or Cu, but is notlimited to these. An impurity-added semiconductor layer (notillustrated) formed of an impurity-added amorphous silicon or the likeis formed between the source electrode 9 and the drain electrode 13, andthe semiconductor active layer 8. The TFT switch 4 for switching isconfigured by these. Note that, at the TFT switch 4, the sourceelectrode 9 and the drain electrode 13 may be formed opposite due to thepolarity of the charges that are collected and accumulated by a lowerelectrode 11.

Further, as shown in FIG. 5, the radiation detection TFT switch 34 isprovided at the pixel 20A, in the same way as the above-described TFTswitch 4. Note that, at the pixel 20A, the source electrode 9 is formedso as to not be connected to (so as to not contact) the signal line 3.Due thereto, at the pixel 20A, the charges collected at the lowerelectrode 11 do not flow-out to the signal line 3 via the radiationdetection TFT switch 34, regardless of the switched state of theradiation detection TFT switch 34.

A TFT protective film layer 30 is formed on substantially the entiresurface of the region that covers the second signal wiring layer andwhere the pixels 20 are provided on the substrate 1 (substantially theentire region), in order to protect the TFT switches 4 and the signallines 3. The TFT protective film layer 30 is formed of, for example,SiN_(x) or the like, and by, for example, CVD.

A coated interlayer insulating film 12 is formed on the TFT protectivefilm layer 30. The interlayer insulating film 12 is formed in a filmthickness of 1 μm to 4 μm by a photosensitive organic material (e.g., apositive photosensitive acrylic resin: a material in which anaphthoquinone diazide positive photosensitizer is mixed together with abase polymer including a copolymer of methacrylic acid and glycidylmethacrylate or the like) having a low permittivity (relativepermittivity εr=2 to 4).

In the radiation detector 10 according to the present exemplaryembodiment, the capacity between the metals that are disposed at theupper layer and the lower layer of the interlayer insulating film 12 iskept low by the interlayer insulating film 12. Further, generally, sucha material also functions as a flattening film, and also has the effectof flattening the steps of the lower layer. In the radiation detector 10according to the present exemplary embodiment, contact holes 17 areformed in the interlayer insulating film 12 and the TFT protective filmlayer 30 at positions opposing the drain electrodes 13.

The lower electrode 11 of the sensor portion 103 is formed on theinterlayer insulating film 12, so as to cover the pixel region whilefilling-in the contact hole 17. The lower electrode 11 is connected tothe drain electrode 13 of the TFT switch 4. If a semiconductor layer 21is thick and around 1 μm, there are hardly any limitations on thematerial of the lower electrode 11 provided that it is electricallyconductive. In such case, the lower electrode 11 may be formed by usingan electrically conductive metal such as an Al-type material, ITO, orthe like.

On the other hand, if the film thickness of the semiconductor layer 21is thin (around 0.2 μm to 0.5 μm), the absorption of light at thesemiconductor layer 21 may be insufficient. Therefore, in order toprevent an increase in leak current due to the illumination of lightonto the TFT switch 4, it is preferable to make the semiconductor layer21 be an alloy that is formed mainly of a light-shielding metal, or alayered film.

The semiconductor layer 21 that functions as a photodiode is formed onthe lower electrode 11. In the present exemplary embodiment, aphotodiode of a PIN configuration, in which an n+ layer, an i layer, anda p+ layer (n+ amorphous silicon, amorphous silicon, p+ amorphoussilicon) are layered, is employed as the semiconductor layer 21, and isformed by layering an n+ layer 21A, an i layer 21B, and a p+ layer 21Cin that order from the lower layer. At the i layer 21B, charges (pairsof a free electron and a free hole) are generated due to light beingilluminated. The n+ layer 21A and the p+ layer 21C function as contactlayers, and electrically connect the lower electrode 11 and an upperelectrode 22, that is described hereinafter, with the i layer 21B.

The upper electrode 22 is formed individually on each of thesemiconductor layers 21. A material having high light transmittance suchas, for example, ITO or IZO (indium zinc oxide) or the like, is used asthe upper electrode 22. In the radiation detector 10 according to thepresent exemplary embodiment, the sensor portion 103 is configured so asto include the upper electrode 22, the semiconductor layer 21, and thelower electrode 11.

A coating-type interlayer insulating film 23, that has openings 27A atportions thereof corresponding to the upper electrodes 22, is formed onthe interlayer insulating film 12, the semiconductor layers 21 and theupper electrodes 22 so as to cover the respective semiconductor layers21.

The common electrode lines 25 are formed on the interlayer insulatingfilm 23, of Al or Cu, or an alloy or a layered film formed mainly of Alor Cu. Contact pads 27 are formed in vicinities of the openings 27A, andthe common electrode lines 25 are electrically connected to the upperelectrodes 22 via the openings 27A of the interlayer insulating film 23.

On the other hand, as shown in FIG. 6, at the radiation detection pixel20B of the radiation detector 10, the radiation detection TFT switch 34is formed such that the source electrode 9 and the signal line 3 areconnected (contact one another). Due thereto, at the radiation detectionpixel 20B, the charges collected by the lower electrode 11 flow-out tothe signal line 3 via the radiation detection TFT switch 34, inaccordance with the switched state of the radiation detection TFT switch34.

In the radiation detector 10 that is formed in this way, as needed, aprotective film is further formed from an insulating material having lowlight absorbance. A scintillator formed from GOS or CsI or the like isaffixed to the surface thereof by using an adhesive resin having lowlight absorbance.

The schematic configuration of the signal detecting circuit 105 of thepresent exemplary embodiment is described next. FIG. 7 is a schematicdrawing of an example of the signal detecting circuit 105 of the presentexemplary embodiment. The signal detecting circuit 105 of the presentexemplary embodiment is configured to include amplification circuits 50and an ADC (analog/digital converter) 54. Note that, although notillustrated in FIG. 7, the amplification circuit 50 is provided for eachsignal line 3. Namely, the signal detecting circuits 105 are configuredso as to have the plural amplification circuits 50 of the same number asthe number of the signal lines 3 of the radiation detector 10.

The amplification circuit 50 is configured by a charge amplificationcircuit, and is configured to include an amplifier 52 such as anoperational amplifier or the like, a capacitor C that is connected inparallel to the amplifier 52, and a switch SW1 for charge resetting thatis connected in parallel to the amplifier 52.

At the amplification circuit 50, when the switch SW1 for chargeresetting is in an OFF state, charges (electric signals) are read-outfrom the TFT switches 4 or the radiation detection TFT switches 34 ofthe pixels 20, and the charges read-out from the TFT switches 4 or theradiation detection TFT switches 34 are accumulated in the capacitor C,and the voltage value outputted from the amplifier 52 is increased inaccordance with the accumulated charge amount.

Further, the control section 106 applies a charge resetting signal tothe switch SW1 for charge resetting, and controls the ON/OFF state ofthe switch SW1 for charge resetting. Note that, when the switch SW1 forcharge resetting is set in an on state, the input side and the outputside of the amplifier 52 are short-circuited, and the charges of thecapacitor C are discharged.

The ADC 54 has the function of, when an S/H (sample-and-hold) switch SWis in an ON state, converting the electric signal, that is the analogsignal inputted from the amplification circuit 50, into a digitalsignal. The ADC 54 successively outputs the electric signals, that havebeen converted into digital signals, to the control section 106.

Note that the electric signals, that are outputted from all of theamplification circuits 50 provided at the signal detecting circuit 105,are inputted to the ADC 54 of the present exemplary embodiment. Namely,the signal detecting circuit 105 of the present exemplary embodiment hasthe one ADC 54 regardless of the number of amplification circuits 50(signal lines 3).

In the present exemplary embodiment, the electric signals of the signallines 3, to which the radiation detection TFT switches 34 of theradiation detection pixels 20B are connected (in FIG. 2, the signallines D3, D4, D5), are detected at the amplification circuits 50 of thesignal detecting circuit 105. The control section 106 compares thevalues of the digital signals converted by the signal detecting circuit105 with a predetermined threshold value for radiation detection, andcarries out detection according to the irradiation of radiation, such asdetecting whether or not radiation has been irradiated or the like, inaccordance with whether or not the values of the digital signals aregreater than or equal to the threshold value. This is a so-calledsynchronization-free configuration in which control signals from thecontrol device 202 are not needed. Note that the detection, by thecontrol section 106, of whether or not radiation has been irradiated isnot limited to comparison with a threshold value for radiationdetection. For example, detection may be carried out on the basis of acondition that is set in advance, such as the number of times ofsensing, or the like.

Note that the “detection” of an electric signal in the present exemplaryembodiment means the sampling of the electric signal.

Next, the flow of operations at the time of imaging a radiographic imageby the radiation imaging device 100 of the above-described configurationis described simply by using FIG. 8.

At the radiation detector 10 of the present exemplary embodiment, evenin a state in which radiation is not being irradiated, charges aregenerated due to dark current or the like, and the charges areaccumulated in the respective pixels 20. Therefore, in the radiographicimaging device 100, a resetting operation, in which the chargesaccumulated in the respective pixels 20 of the radiation detector 10 areremoved and eliminated, is carried out repeatedly also during thestandby state. The information expressed by the charges that areread-out in this resetting operation is utilized in correcting noise(offset) that arises in the radiographic image due to dark current orthe like. Further, in the present exemplary embodiment, the state inwhich the power of the radiation detector 10 (the radiographic imagingdevice 100) is OFF is a standby period.

The radiographic imaging device 100 captures a radiographic image bydetecting the start of irradiation of radiation and starts theaccumulation of charges at the respective pixels 20 of the radiationdetector 10. At the time when imaging of a radiographic image is carriedout, the control device 202 notifies the radiographic imaging device 100of the move to an imaging mode.

When the radiographic imaging device 100 is notified of the move to theimaging mode, the radiographic imaging device 100 moves on to aradiation detection period in which detection of the start ofirradiation of radiation is carried out (this is a standby state for theirradiation of radiation). When the start of irradiation of radiation isdetected, the radiographic imaging device 100 moves on to anaccumulation period in which charges are accumulated in the respectivepixels 20 of the radiation detector 10. A predetermined time after thedetecting of the start of irradiation of radiation, or when thecompletion of the accumulation period is detected, the radiographicimaging device 100 moves on to a read-out state in which the accumulatedcharges are read-out, and, after the reading-out of the charges ends,again moves on to the standby state. Note that offset information may becontinued to be acquired after the end of the reading-out of thecharges.

Next, the flow of operations at the time of imaging a radiographic imageby the radiation imaging device 100 according to the present exemplaryembodiment is described in detail. A time chart, that shows in detailthe flow of operations of the radiographic imaging device 100 accordingto the present exemplary embodiment at the time of imaging aradiographic image, is shown in FIG. 9. Note that FIG. 9 is a time chartthat shows in detail operations during a radiation detection period thatis after the aforementioned standby period has ended, and theradiographic imaging device 100 has moved on to the imaging mode.

In the radiographic imaging device 100 of the present exemplaryembodiment, during the radiation detection period, the scan signalcontrol circuit 104 is controlled, and scan signals of gate potentialVg1 are outputted from the scan signal control circuits 104 to therespective scan lines 101 (G1 through Gn). Due thereto, the TFT switches4 of the respective pixels 20 are maintained in OFF states.

On the other hand, the radiation detection control circuit 108 iscontrolled, and scan signals of gate potential Vgh are outputted fromthe control circuit 108 to the respective radiation detection scan lines109 (Ch1, Ch2). Due thereto, during the radiation detection period, theradiation detection TFT switches 34 of the respective pixels 20 aremaintained in ON states. At this time, at the pixels 20A, the radiationdetection TFT switches 34 are not connected to the signal lines 3, andtherefore are in ON states, but charges are not outputted to the signallines 3 via the radiation detection TFT switches 34. On the other hand,at the radiation detection pixels 20B, the radiation detection TFTswitches 34 are connected to the signal lines 3, and therefore, chargesare outputted to the signal lines 3 via the radiation detection TFTswitches 34, in accordance with their being in ON states. Further, inthe present exemplary embodiment, the electric signals that flow to thesignal lines 3 are converted into digital data and sampling thereof isrepeated by the amplification circuits (CA: charge amplifiers) 50 of thesignal detecting circuit 105 at a predetermined cycle 1H.

The control section 106 compares the digital data values, that wereconverted by the signal detecting circuit 105, of the signal lines 3 towhich the radiation detection pixels 20B are connected, with apredetermined threshold value for detecting the start of irradiation ofradiation, and, in accordance with whether or not this threshold valueis exceeded, carries out detection of whether or not the irradiation ofradiation has started. If the threshold value is exceeded, the controlsection 106 detects that the irradiation of radiation has started, andthe radiographic imaging device 100 moves on to the aforementionedaccumulation period.

In the accumulation period, scan signals of the gate potential Vg1 areoutputted from the radiation detection control circuit 108 to therespective radiation detection scan lines 109 (Ch1, Ch2). Due thereto,the radiation detection TFT switches 34 of the respective pixels 20 aremaintained in OFF states. Due to the radiation detection TFT switches 34being set in OFF states, at the radiation detection pixels 20B as well,the charges of the sensor portions 103 can be accumulated during theaccumulation period. Accordingly, a radiographic image may be generatedby using the charges outputted from the radiation detection pixels 20B(the electric signals corresponding to the charges).

Note that the flow of operations at the time of imaging a radiographicimage by the radiographic imaging device 100 according to the presentexemplary embodiment is not limited to the above. Another example isdescribed with reference to FIG. 10. Note that, similarly toabove-described FIG. 9, FIG. 10 as well is a time chart that shows indetail operations during a radiation detection period that is after theaforementioned standby period has ended, and the radiographic imagingdevice 100 has moved on to the imaging mode.

In the case shown in FIG. 10, during the radiation detection period, thescan signal control circuit 104 is controlled, and scan signals of thegate potential Vgh are outputted repeatedly at the predetermined cycle1H that is a resetting cycle, from the scan signal control circuit 104to the respective scan lines 101 (G1 through Gn). Due thereto, the TFTswitches 4 of the respective pixels 20 enter into ON states, and theresetting operation, that removes the charges accumulated in therespective pixels 20, is executed repeatedly at the resetting cycle 1H.

On the other hand, while scan signals of the gate potential Vgh for theresetting operation are being outputted to the respective scan lines 101as described above, scan signals of the gate potential Vg1 are outputtedfrom the radiation detection control circuit 108 to the respectiveradiation detection scan lines 109 (Ch1, Ch2). Due thereto, during theresetting operation, the radiation detection TFT switches 34 of therespective pixels 20 enter into OFF states. Thereafter, when the scansignals flowing to the respective scan lines 101 become the gatepotential Vg1 and the TFT switches 4 enter into OFF states, scan signalsof the gate potential Vgh are outputted from the radiation detectioncontrol circuit 108 to the radiation detection scan lines 109, and theradiation detection TFT switches 34 of the respective pixels 20 enterinto ON states. In the same way as described above, in accordance withthe radiation detection TFT switches 34 entering into ON states, theelectric signals that flow to the signal lines 3 are converted intodigital data, and sampling thereof is repeated by the amplificationcircuits (CA: charge amplifiers) 50 of the signal detecting circuit 105.Moreover, as described above, the control section 106 compares thedigital data values of the signal lines 3 to which the radiationdetection pixels 20B are connected, which digital data values wereconverted by the signal detecting circuit 105, and the predeterminedthreshold value for detecting the start of irradiation of radiation.When the threshold value is exceeded, it is detected that irradiation ofradiation has started, and the radiographic imaging device 100 moves onto the accumulation period. Still further, in this case as well, duringthe accumulation period, due to scan signals of the gate potential Vg1being outputted from the radiation detection control circuit 108 to therespective radiation detection scan lines 109 (Ch, Ch2), charges can beaccumulated in the sensor portions 103 during the accumulation period atthe radiation detection pixels 20B as well. Accordingly, a radiographicimage may be generated by also the using the charges outputted from theradiation detection pixels 20B (the electric signals corresponding tothe charges).

Note that, in the above explanation, the start of irradiation ofradiation is detected by, for each of the signal lines 3, sampling theelectric signal, and comparing the electric signal with the thresholdvalue for detecting the start of irradiation of radiation. However, thestart of irradiation of radiation may be detected at each block that isformed from a predetermined number of the pixels 20. An example of acase of carrying out detection per block is shown in FIG. 11 and FIG.12.

FIG. 11 illustrates a case in which four (four rows) of the radiationdetection scan lines 109 are connected, as a single radiation detectionscan line 109 (Ch), to the radiation detection control circuit 108. Oneblock 40 is the pixels 20 that are configured by the one radiationdetection scan line 109 (Ch) and four (four columns) of the signal lines3. Concretely, in the case of the radiographic imaging device 100 (theradiation detector 10) shown in FIG. 2, the one block 40 is formed by 32of the pixels 20, which are the pixels 20 of eight rows×the pixels 20 offour columns=32 of the pixels 20.

When detecting the start of irradiation of radiation, scan signals, thatare such that the radiation detection TFT switches 34 are turned ON, areoutputted successively from the radiation detection control circuit 108to the radiation detection scan lines 109 (Ch1 through Chm). In thesignal detecting circuit 105, the average charge amount, that isgenerated in accordance with the irradiated radiation, is acquired perblock 40 as shown in FIG. 12, by reading the average charge amounts (theelectric signals corresponding to the average charge amounts) of thesignal lines 3, to which the radiation detection pixels 20B areconnected, by time division at the amplification circuits 50 per block40 (CA1 through CAz). Note that FIG. 12 shows that, the higher thedensity of the block 40, the greater the average charge amount, andaccordingly, the greater the dose of the irradiated radiation.

For each block 40, the control section 106 compares the digital datavalue of the average charge amount that was read with a threshold valuefor detecting the start of irradiation of radiation. In a case in whichthe threshold value is exceeded, the start of irradiation of radiationis detected.

As described above, the radiation detector 10 of the radiographicimaging device 100 of the present exemplary embodiment has: the pixels20A that have the sensor portion 103 that generates charges inaccordance with light that has been converted from irradiated radiation,the TFT switch 4 that outputs, to the signal line 3, the chargesread-out from the sensor portion 103, and the radiation detection TFTswitch 34 that is not connected to the signal line 3; and the radiationdetection pixels 20B that have the sensor portion 103, the TFT switch 4,and the radiation detection TFT switch 34 that is connected to thesignal line 3 and outputs, to the signal line 3, the charges read-outfrom the sensor portion 103. The control terminal of the radiationdetection TFT switch 34 is connected to the radiation detection scanline 109, and the on/off state is controlled by scan signals outputtedfrom the radiation detection control circuit 108.

In this way, in the radiation detector 10 of the present exemplaryembodiment, during the accumulation period and the read-out period, OFFsignals flow from the radiation detection control circuit 108 to theradiation detection scan lines 109, and, due thereto, the radiationdetection TFT switches 34 can be set in OFF states. Due thereto, anincrease in the wiring capacity of the signal lines 3, that is due tothe radiation detection pixels 20B being connected, may be prevented. Ofthe parasitic capacity that arises at the radiation detector 10, theparasitic capacity that is due to the pixel capacity of the pixels 20 issubjective. For example, in a case in which the parasitic capacity perpixel 20 is around 2 pF and 100 of the radiation detection pixels 20Bare connected, the parasitic capacity increases as much as 200 pf. Onthe other hand, because the signal line capacity of the signal line 3 isaround 200 pF, by providing the radiation detection pixels 20B, thewiring capacity (parasitic capacity) doubles. In the present exemplaryembodiment, by setting the radiation detection TFT switches 34 in OFFstates as described above, an increase in parasitic capacity due to theradiation detection pixels 20B may be prevented.

The difference in the wiring capacities of the signal lines 3, to whichthe radiation detection pixels 20B are connected, and the signal lines3, to which only the pixels 20A are connected and the radiationdetection pixels 20B are not connected, may be prevented from becominglarge. Accordingly, detection according to the irradiation of radiationmay be carried out while maintaining the quality of the radiographicimage as is.

Further, in the present exemplary embodiment, the radiation detectionpixels 20B also are configured so as to have the TFT switch 4. Because aradiographic image can be generated by using the charge information(electric signals) read-out from the radiation detection pixels 20B, theradiation detection pixels 20B becoming point defects may be suppressed,and the quality of the generated radiographic image may be maintained.

Further, in the present exemplary embodiment, by providing the radiationdetection scan line 109 between two of the scan lines 101, there is aso-called mirror-reversed pixel pattern in which the pixels 20A and theradiation detection pixels 20B have line symmetry across the radiationdetection scan line 109. Due to such a configuration, as compared with acase in which the wire of the radiation detection scan line 109 isprovided for each row of pixels 20, the number of wires of the radiationdetection scan lines 109 may be halved, and an increase in noise due tothe increase in the radiation detection scan lines 109 may besuppressed, the quality of the radiographic image may be maintained, anda decrease in yield may be suppressed.

Further, in the present exemplary embodiment, during the radiationdetection period, scan signals, that set in the radiation detection TFTswitches 34 in ON states, are outputted to the radiation detection scanlines 109, and the start of irradiation of radiation may be detectedwhile successively resetting the pixels 20. By doing so, artifactscaused by the reset cycle changing may be prevented, and therefore, thequality of the radiographic image may be maintained.

Further, in the present exemplary embodiment, due to the configurationin which the radiation detection TFT switches 34 are provided at thepixels 20A as well, the pixels 20A and the radiation detection pixels20B can be made to have substantially the same configurations.Generally, when inspecting the radiation detector 10 by an inspectiondevice, the radiation detection pixels 20B being detected as defective(errors), due to the difference between the shape (pattern) of thepixels 20A and the shape of the radiation detection pixels 20B, can beprevented. Accordingly, limitations on an inspection device (e.g., anoptical inspection device) may be avoided. Further, for example, if theshape (pattern) of the pixel 20A and the shape (pattern) of theradiation detection pixels 20B differ greatly, a repeating pattern of amask that is used in manufacturing the radiation detector 10 may not beused, and therefore, there are cases in which manufacturing isdifficult. However, because manufacturing can be carried out by using arepeating pattern of a mask, the radiation detector 10 may be made easyto manufacture.

Note that, in the present exemplary embodiment, a case in which thestart of irradiation of radiation is detected, have been described.However, the present invention is not limited thereto, and may carry outother detection according to the irradiation of radiation. For example,the present invention may be utilized in controlling the irradiation ofradiation, in a case in which there is synchronization with the controldevice 202 of the radiation in FIG. 1. As shown in FIG. 13, sampling, inwhich electric signals, that flow to the signal lines 3 to which theradiation detection pixels 20B are connected, are converted into digitaldata by the signal detecting circuit 105 and detection of radiation iscarried out, is repeated at the predetermined cycle 1H also during theaccumulation period after detection of the start of irradiation ofradiation, and the values of the digital data of the signal lines 3 towhich the radiation detection pixels 20B are connected are compared witha predetermined threshold value for radiation detection, and theirradiation of radiation is stopped when the cumulative amount exceedsthe threshold value, or, the time when the cumulative amount will exceedthe threshold value is predicted and the irradiation of radiation isstopped at this time when exceeding of the threshold value is predicted.Further, similarly, the present invention may also be applied to realtime gain switching, such as achieving the optimal gain that correspondsto the dose. In a configuration in which the capacity of the capacitor Cof the amplifier 52 that is a charge amplifier can be changed to severallevels (C1, C2, C3 . . . ) in the signal detecting circuit 105 such asshown in FIG. 7, in a case in which it is determined, from the value ofthe digital data of the signal line 3 to which the radiation detectionpixel 20B is connected, that the dose is low, the capacity of thecapacitor is changed and the amplification factor of the amplifier israised such that the S/N ratio becomes higher, and, in a case in whichit is determined that the dose is high, the amplification factor of theamplifier is lowered and the amplification factor of the signals fromthe pixels 20A that are read-out thereafter is changed so as to becomeoptimal so that the signals are not saturated.

Further, in the radiation detector 10 (see FIG. 2) of the radiationimaging device 100 of the present exemplary embodiment, the radiationdetection pixels 20B are connected to some of the signal lines 3.However, the present invention is not limited thereto, and the radiationdetection pixels 20B may be provided at positions connected to all ofthe signal lines 3.

Further, in the present exemplary embodiment, a case in which one of theradiation detection scan lines 109 is provided per two of the scan lines101 (so as to correspond to two rows of the pixels 20), have beendescribed. However, the present invention is not limited thereto, andmay be configured such that one of the radiation detection scan lines109 is provided per another number of the scan lines 101 (per pixels 20of another number of rows). Further, in the present exemplaryembodiment, each two of the radiation detection scan lines 109(corresponding to four rows of the pixels 20) are connected as oneradiation detection scan line 109 (Ch) to the radiation detectioncontrol circuit 108. However, the present invention is not limitedthereto, and each of another number of the radiation detection scanlines 109 (corresponding to another number of rows of the pixels 20) maybe connected as one radiation detection scan line 109 (Ch) to theradiation detection control circuit 108.

Further, in the present exemplary embodiment, a case in which the pixels20A of the radiation detector 10 also have the radiation detection TFTswitches 34, have been described. However, as shown in FIG. 14, thepixels 20A may be configured so as to not have the radiation detectionTFT switches 34. Also in the radiation detector 10 of the presentexemplary embodiment that is shown in FIG. 2, the radiation detectionTFT switches 34 of the pixels 20A are not connected to the signal lines3, and charges are not read-out via the radiation detection TFT switches34. Therefore, in a case in which the radiation detection TFT switches34 are not provided at the pixels 20A as shown in FIG. 14, detectionaccording to the irradiation of radiation may be carried outappropriately.

Further, in the present exemplary embodiment, a case in which anindirect-conversion type radiation detector 10 that generates charges inaccordance with light obtained by irradiated radiation being convertedby a scintillator, have been described. However, the present inventionis not limited thereto, and may be applied to a direct-conversion typethat directly converts radiation into charges at a semiconductor layerand accumulates the charges. In this case, the sensor portions in adirect-conversion type generate charges due to radiation beingirradiated thereon.

In addition, the configurations, operations and the like of theradiation imaging device 100, the radiation detector 10, the pixels 20and the like that were described in the present exemplary embodiment areexamples, and may, of course, be changed in accordance with thesituation within a range that does not deviate from the gist of thepresent invention.

Further, in the present exemplary embodiment, the radiation of thepresent invention is not particularly limited, and X-rays, γ-rays or thelike can be used.

What is claimed is:
 1. A radiation detector comprising: a plurality ofsignal lines, a plurality of first pixels including, a first sensorportion that generates charges in accordance with irradiated radiation,and a first switching element that reads-out the charges generated atthe first sensor portion and outputs the charges to a signal line; aplurality of second pixels including, a second sensor portion thatgenerates charges in accordance with irradiated radiation, a secondswitching element that reads-out the charges generated at the secondsensor portion and outputs the charges to a signal line, and a radiationdetection switching element that reads-out the charges generated at thesecond sensor portion and outputs the charges to the signal line towhich the charges read-out by the second switching element flow; aplurality of scan lines that are formed from at least one of a scan linegroup formed from scan lines to which control terminals of the firstswitching elements are connected and through which control signals thatswitch the first switching elements flow, and scan lines to whichcontrol terminals of the second switching elements are connected andthrough which control signals that switch the second switching elementsflow, or a scan line group to which the control terminals of the firstswitching elements and the control terminals of the second switchingelements are connected and through which control signals that switch thefirst switching elements and the second switching elements flow; and aplurality of radiation detection scan lines that are provided betweenpredetermined scan lines among the plurality of scan lines, and to whichcontrol terminals of the radiation detection switching elements areconnected, and through which radiation detection control signals thatswitch the radiation detection switching elements flow, wherein theplurality of signal lines are formed from either a signal line groupformed from signal lines to which the charges output from the firstpixels and the charges output from the second pixels flow, or a signalline group formed from signal lines to which the charges output from thefirst pixels and the charges output from the second pixels flow andsignal lines to which the charges output from the first pixels flow. 2.The radiation detector of claim 1, wherein each of the first pixelsincludes the radiation detection switching element whose controlterminal is connected to the radiation detection scan line, that is notconnected to a signal line.
 3. The radiation detector of claim 2,wherein the first pixels and the second pixels are configured to haveshapes that are line-symmetrical across the radiation detection scanlines.
 4. A radiographic imaging device comprising: the radiationdetector of claim 3; a radiation detection control circuit that outputsthe radiation detection control signals to the radiation detectionswitching elements of the radiation detector; and detecting section thatcarry out predetermined detection according to irradiation of radiation,on the basis of electric signals corresponding to the charges that areoutputted to the signal lines from the radiation detection switchingelements of the second pixels.
 5. The radiation detector of claim 2,wherein the plurality of radiation detection scan lines are connected,per each predetermined number thereof, to a radiation detection controlcircuit from which the radiation detection control signals areoutputted.
 6. A radiographic imaging device comprising: the radiationdetector of claim 2; a radiation detection control circuit that outputsthe radiation detection control signals to the radiation detectionswitching elements of the radiation detector; and detecting section thatcarry out predetermined detection according to irradiation of radiation,on the basis of electric signals corresponding to the charges that areoutputted to the signal lines from the radiation detection switchingelements of the second pixels.
 7. The radiation detector of claim 1,wherein the first pixels and the second pixels are configured to haveshapes that are line-symmetrical across the radiation detection scanlines.
 8. The radiation detector of claim 7, wherein the plurality ofradiation detection scan lines are connected, per each predeterminednumber thereof, to a radiation detection control circuit from which theradiation detection control signals are outputted.
 9. A radiographicimaging device comprising: the radiation detector of claim 7; aradiation detection control circuit that outputs the radiation detectioncontrol signals to the radiation detection switching elements of theradiation detector; and detecting section that carry out predetermineddetection according to irradiation of radiation, on the basis ofelectric signals corresponding to the charges that are outputted to thesignal lines from the radiation detection switching elements of thesecond pixels.
 10. The radiation detector of claim 1, wherein theplurality of radiation detection scan lines are connected, per eachpredetermined number thereof, to a radiation detection control circuitfrom which the radiation detection control signals are outputted.
 11. Aradiographic imaging device comprising: the radiation detector of claim1; a radiation detection control circuit that outputs the radiationdetection control signals to the radiation detection switching elementsof the radiation detector; and detecting section that carry outpredetermined detection according to irradiation of radiation, on thebasis of electric signals corresponding to the charges that areoutputted to the signal lines from the radiation detection switchingelements of the second pixels.
 12. The radiographic imaging device ofclaim 11, wherein, during a detection period in which a start ofirradiation of radiation is detected by the detecting section, controlsignals that set the first switching elements and the second switchingelements in OFF states flow to the scan lines, and the radiationdetection control signals that set the radiation detection switchingelements in ON states flow to the radiation detection scan lines. 13.The radiographic imaging device of claim 12, wherein, during a detectionperiod in which a start of irradiation of radiation is detected by thedetecting section, a resetting operation, that resets chargesaccumulated in the first pixels and the second pixels is repeated at apredetermined cycle, by flowing control signals that set the firstswitching elements and the second switching elements in ON states to thescan lines.
 14. The radiographic imaging device of claim 12, wherein,when the first switching elements and the second switching elements areset in ON states and the charges for imaging radiographic image areoutputted from the first pixels and the second pixels to the signallines, the radiation detection switching elements are set in OFF states.15. The radiographic imaging device of claim 11, wherein, during adetection period in which a start of irradiation of radiation isdetected by the detecting section, a resetting operation, that resetscharges accumulated in the first pixels and the second pixels isrepeated at a predetermined cycle, by flowing control signals that setthe first switching elements and the second switching elements in ONstates to the scan lines.
 16. The radiographic imaging device of claim15, wherein, when the first switching elements and the second switchingelements are set in ON states and the charges for imaging radiographicimage are outputted from the first pixels and the second pixels to thesignal lines, the radiation detection switching elements are set in OFFstates.
 17. The radiographic imaging device of claim 11, wherein, whenthe first switching elements and the second switching elements are setin ON states and the charges for imaging radiographic image areoutputted from the first pixels and the second pixels to the signallines, the radiation detection switching elements are set in OFF states.18. A radiographic imaging system comprising: an irradiation device thatirradiates radiation; and the radiographic imaging device of claim 11that detects the radiation irradiated from the irradiation device andacquires a radiographic image corresponding to detected radiation.